The Democratic nominee for president has the luxury of an all-star lineup of political and pop-culture talent to make her case. No one is more talented at talking to the American people in conversational manner than her husband, Bill Clinton. And President Obama is the most gifted politician of his generation in soaring oratory.

For years, Clinton has maintained an arms-length relationship with the truth, grudgingly revealing embarrassing facts only when forced and speaking falsehoods even on trivial matters.

Both men were at the top of their game this week. But neither dared address the reckless behavior — or in the words of FBI Director James Comey, “extremely careless” — that fuels doubts about Hillary Clinton in the first place. As secretary of state, Clinton set up private servers in her house and sent and received email containing classified information.

That conduct undermines every increasingly strident attack leveled at Republican Donald Trump this week in Philadelphia.

The email scandal may have irreparably exposed Clinton’s trust problem. It comes on top of clear falsehoods she spun in the wake of a terrorist attack that killed four Americans in Benghazi, Libya, in 2011. Emails show irrefutably that she told one story in private — the true one, involving an organized terrorist attack — and another one in public — a now-discredited narrative that an obscure internet film sparked a spontaneous protest.

Hillary Clinton's Trust Deficit

CNN/ORC 7-24

Don't trust

68%

Trust

30%

Spread

38%

NYT/CBS Poll 7-12

Don't Trust

67%

Trust

28%

Spread

39%

Source: RealClearPolitics

For years, Clinton has maintained an arms-length relationship with the truth, grudgingly revealing embarrassing facts only when forced and speaking falsehoods even on trivial matters. During a South Asia goodwill tour, for instance, she claimed to have been named after the explorer Sir Edmund Hillary. But she was born six years before he climbed Mount Everest.

In 2008, she claimed to have risked her life landing amid sniper fire on a trip to war-torn Bosnia in 1996. Witnesses, including actor and comedian Sinbad, said it was not so.

Perhaps Clinton will overcome all this with a great speech Thursday night and ride the post-convention bounce into the heart of the general election campaign. But the early returns are lackluster. A Rasmussen poll taken Tuesday and Wednesday show Clinton with a 1-point lead, essentially a dead heat. A Clout Research survey released Wednesday shows Clinton with a too-close-for comfort 3-point lead in the deep blue state of Oregon. Several other recent surveys show Trump maintaining a post-RNC lead.

Researchers at Yale University believe the root of Clinton’s problems with trust run deeper than getting caught in the act of lying. After all, Trump is a serial exaggerator who has switched positions on multiple issues. How can he be viewed as more trustworthy? The answer, according to Yale University professor David Rand and graduate student Jillian Jordan, rests with psychology.

Hillary Clinton's Favorability

CNN/ORC 7-24

Unfavorable

55%

Favorable

39%

Spread

16%

Gallup 7-25

Unfavorable

57%

Favorable

38%

Spread

19%

NYT/CBS 7-12

Unfavorable

56%

Favorable

31%

Spread

25%

Source: RealClearPolitics

Writing this week in the Daily Mail, they argue that experiments they have run show that people are viewed as less trustworthy when people think they are calculating.

“To win, Clinton needs to convince voters that her calculations have their best interests at heart — a major goal of this week’s Democratic National Convention,” they wrote.

Rand and Jordan wrote that candidates who take time to make decisions and carefully weigh pros and cons can turn off voters — even ones who agree with them. Trump’s shoot-from-the-hip style, meanwhile, endears him to voters — at least those who share his values.

"Our studies may also help to shed light on Trump's appeal," they wrote. "One of his greatest advantages appears to be the authenticity that he conveys with his emotionally charged behavior … In contrast, Clinton's persona is often unattractive even to those who support her values — because it suggests that she may not stand by those values when the cost is too high."

The insight dovetails perfectly with the the spectacle of Clinton's well-documented struggles to bring supporters of Sen. Bernie Sanders into the fold — voters for whom Clinton should be an easy choice over Trump, based on ideology.